4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Woodhouse <dwmw@xxxxxxxxxxxx> commit e70e5892b28c18f517f29ab6e83bd57705104b31 upstream. Convert all indirect jumps in hyperv inline asm code to use non-speculative sequences when CONFIG_RETPOLINE is enabled. Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: gnomes@xxxxxxxxxxxxxxxxxxx Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: thomas.lendacky@xxxxxxx Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Jiri Kosina <jikos@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxx> Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxxx> Cc: Paul Turner <pjt@xxxxxxxxxx> Link: https://lkml.kernel.org/r/1515707194-20531-9-git-send-email-dwmw@xxxxxxxxxxxx [ backport to 4.4, hopefully correct, not tested... - gregkh ] Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hv/hv.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -31,6 +31,7 @@ #include <linux/clockchips.h> #include <asm/hyperv.h> #include <asm/mshyperv.h> +#include <asm/nospec-branch.h> #include "hyperv_vmbus.h" /* The one and only */ @@ -103,9 +104,10 @@ static u64 do_hypercall(u64 control, voi return (u64)ULLONG_MAX; __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8"); - __asm__ __volatile__("call *%3" : "=a" (hv_status) : + __asm__ __volatile__(CALL_NOSPEC : + "=a" (hv_status) : "c" (control), "d" (input_address), - "m" (hypercall_page)); + THUNK_TARGET(hypercall_page)); return hv_status; @@ -123,11 +125,12 @@ static u64 do_hypercall(u64 control, voi if (!hypercall_page) return (u64)ULLONG_MAX; - __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi), + __asm__ __volatile__ (CALL_NOSPEC : "=d"(hv_status_hi), "=a"(hv_status_lo) : "d" (control_hi), "a" (control_lo), "b" (input_address_hi), "c" (input_address_lo), "D"(output_address_hi), - "S"(output_address_lo), "m" (hypercall_page)); + "S"(output_address_lo), + THUNK_TARGET(hypercall_page)); return hv_status_lo | ((u64)hv_status_hi << 32); #endif /* !x86_64 */